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Engine basics => Engine set up tips => Topic started by: Gary Anderson on June 29, 2009, 02:39:25 PM
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Hi Randy,
The evolution 36 I have seems to run well, its just that I noticed it loses a lot of fuel through the front engine bearing. Is there something I could do to stop the engine from doing this? Is this something normal with this engine. Doesn't bother me much because I'm using the motor on a profile plane. If I was using this engine in a build up fuselage I wouldn't care for the engine doing this. I know on my old Merco engines a better bearing was installed and it helped the problem. My Super Tigre 60 doesn't seem to have a leaking bearing problem nor my Double Star 61 RE engine. I believe the evolution 36 would run a little better if I could stop the leak. Maybe I'm just running the evolution to rich??? I tried leaning her out a little more and she still leaked, not as much but still did leak. The engine isn't very old was just wondering if anyone else has noticed this problem. I would appreciate any input, thank you Gary
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Clarence Lee (former RCM engine columnist) claims that the leakage is primarily due to a "loose" clearance between the OD of the crankshaft and ID of the crankcase boring---between the two bearings.
Sometimes a shielded front bearing will help with the blow-out, but also people suggest cutting (or scratching) a groove from the front bearing housing to the venturi intake hole--so that in the updraw, the excess oil will be drawn back to the venturi and into the crankcase. I defer to wiser heads in this regards!
Some point out that this oil provides necessary (or at least some) lubrication to the front bearing. You may have a lot more than is necessary.
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Best way is to change out the front bearing with a sealed bearing
Randy